Austria did not manufacture the Mosin Nagnt rifle. They did have them in hand though acquiring them primarily through capture during the Balkan Wars of WW1. If it is shorter than a normal 91/30 you might be onto something or not. The guys on here that are very good at this could help you immediately...

Is it just me or does the muzzle look off center to the mount and the bracket sure looks off center on the bottom of the barrel. If the barrel is off center that might explain why the front sight is so far to the left to bring the point of impact in that direction.